Betty Bryant played the female lead in the first Australian film to win international success, 40,000 Horsemen, but, though she was a successful actress and singer, she will be best remembered as a great humanitarian, one of the founders of the Foundation for the Peoples of the South Pacific (FSP), which is now an international network of development agencies, FSPI.

Born in Bristol in 1920, she was four years old when her father died and her mother migrated to Melbourne, Australia. A former professional singer, her mother taught her how to sing popular songs. In 1932, when her mother married again, they moved to Sydney where, while still a teenager, Betty achieved some success in radio, starring in a popular programme, The Youth Show. She also worked in repertory, and sang with dance bands. She is credited with introducing the Mitchell Parish/Peter De Rose standard "Deep Purple" to Australian audiences in 1939 - the song went on to figure in the hit parade for weeks.

While sunning on Bondi Beach, Bryant was spotted by a talent agent who introduced her to the American head of Universal Studios in Sydney, Hercules McIntyre. The country's most famous film production team, Charles and Elsa Chauvel, were in pre-production of a big film set in the First World War, and had launched a nationwide search for a leading lady. Universal were to distribute it, and McIntyre suggested they test Bryant, who was given the role in 40,000 Horsemen (which started filming in 1939, but was not generally released until 1941).

Advertised as "Magnificent in its Inspired Conception", the film was written by Elsa (billed in the credits as "Mrs Chauvel") and paid tribute to the Australian Light Horse regiment, who were encamped in Palestine on behalf of the British Empire and fought heroically to defeat the powerful and well-armed Ottoman Turks. Bryant played Juliette Rouget, a beautiful French spy whose disguise as an Arab boy is discarded when she falls in love with a trooper - played by a young actor who became a leading Australian star during the next decade, Chips Rafferty. The New York Times found the romantic scenes "foolish", but praised the "brawling, boisterous" film that had "the sweat and sound of battle in it", and the climactic cavalry charge was unanimously praised.

The enormously successful film brought fame to Bryant, and the enthusiasm with which she subsequently entertained the troops, and her victory in a fund-raising Red Cross drive for support of Australian servicemen in South-East Asia, earned her the title "The Red Cross Queen". In 1941 she attended a premiere of 40,000 Horsemen in Singapore, after which she toured camps as far north as Borneo. During the tour, she was introduced to an American, Maurice "Red" Silverstein, who was South-East Asia Director for MGM, and they were married in Sydney in August, 1941, journeying to America for their honeymoon just before Pearl Harbor.

Silverstein was promptly recruited into the Intelligence Service of the US Armed Forces, and his wife planned to resume her acting career when MGM cast her as Greer Garson's daughter-in-law in their prestigious movie Mrs Miniver, but she had to withdraw from the film (and was replaced by Teresa Wright) when she found she was expecting her first child.

The couple were to have three children, and for the next 20 years Bryant concentrated on raising her family. At the end of the Second World War, her husband returned to MGM, where he rose to become President of MGM International.

In 1963 the Silversteins met Father Stan Hosie, a Marist Catholic priest, who told them of the work of missions in Melanesia and Polynesia, and together they conceived the notion of an organisation to develop areas of health, education, agriculture and business to service the needs of the peoples of these nations. In 1966 the Foundation for the Peoples of the South Pacific was launched by their fellow supporters Sir Peter Ustinov and Sophia Loren, and is acknowledged to have made a positive difference to the lives of people throughout Africa, Asia and the Pacific.

Bryant's tireless activities included travelling to every island nation to meet government and community leaders. Through her husband and MGM, she provided offices plus accounting and legal services, and she set up a "thrift shop" in Carnegie Hall, New York, to which friends contributed clothes and furnishings to raise money for the FSP. The organisation founded by Bryant, her husband (who died in 1999) and Hosie is now a global network with member organisations in over 60 nations.

Lelei TuiSamoa LeLaulu, president of the US office, now known as Counterpart International, said:

In all these countries, they adored Betty for her endless kindness and her sense of delight. Betty taught us humility and reminded us that we learned far more from people we "helped" than we ever taught them.

In 2000 she and Father Stan Hosie were given humanitarian service awards by Hillary Clinton.